Place potato starch in a large bowl. Pat chicken wings dry with paper towels; add to potato starch and toss until evenly coated.

Fit a large cast-iron skillet or other heavy straight-sided skillet (not nonstick) with deep-fry thermometer; pour in oil to measure 1" and heat over medium-high heat until thermometer registers 325°.

Working in 3 batches, fry chicken wings, turning often with tongs and adjusting heat to maintain temperature between 300°–325°, until golden, about 5 minutes. Transfer wings to a wire rack set inside a baking sheet.

Increase oil temperature to 375°. Working in 3 batches, fry chicken until golden brown and crisp, about 5 minutes. Transfer wings back to rack, brush liberally with reserved sauce, and top with sesame seeds.